1. Field of the Invention
A heating or air conditioning unit for a motor vehicle having a plurality of independent temperature control regions.
2. Description of Related Art
U.S. Pat. No. 4,482,009 discloses a conventional heating or air conditioning unit, including a fan and a heater, which divides the airstream downstream of the heater. Two ducts leading to the vehicle front compartment distribute conditioned air to the regions for the driver seat and passenger seat, and two ducts leading to the vehicle rear compartment distribute conditioned air to the regions for the seat behind the driver and the seat behind the passenger. Air control elements arranged at the branching points of the air ducts control the quantity of air supplied to each region; however, independent temperature control is only possible between the front and rear zones. Additional air control elements provided further downstream allow the air stream to the front zone to mix with the air stream to the rear zone; however, temperature control is still dependent on the position of the air quantity control elements for the other regions.
DE-A 39 40 361 discloses another conventional heating or air conditioning unit providing conditioned air to the rear zone of a motor vehicle. A first air duct conducts cold air and a second air duct conducts hot air. Air from the first and second ducts is combined in a mixing chamber so as to set the desired temperature of the air stream that goes to the rear zone. One disadvantage of this conventional arrangement is a duct conducting conditioned air to the foot region of the rear zone branches off from the hot air duct upstream of the mixing chamber, hence its temperature is dependent on the temperature setting in the front zone. Another disadvantage is the considerable amount of space required in the rear zone to control the amount of air to the rear zone.
An object of the invention is to provide a heating or air conditioning unit for a vehicle having a plurality of different regions in front and rear sections on both sides of a passenger compartment. A further object of the invention is to provide improved temperature setting convenience by providing a temperature setting for each region which is independent of the temperature setting in any other region, and to provide a space-saving construction.
A particular advantage of the invention is that the temperature can be individually set in a simple manner for at least four conditioned air regions in the motor vehicle passenger compartment. The temperature of the air stream leading to a conditioned air region is set directly in close proximity to a heater unit, thereby avoiding interaction or exchange between air streams of different conditioned air regions. Consequently, a separate temperature setting for different regions in each of four sections of the passenger compartment (e.g. driver side front seat, driver side rear seat, passenger side front seat, and passenger side rear seat) can be achieved without being influenced by the temperature setting for any other region.
Another advantage of the present invention is that the temperature setting for each region is established in close proximity to the heater unit. Therefore, obtaining separate temperature settings for at least four conditioned air regions does not require any more space than is required by conventional heating and air conditioning units to obtain separate temperature settings for only two conditioned air regions.
According to one embodiment of the present invention, the heater unit is divided into four heater core segments through which separate portions of an input air stream are conducted. Each portion of the air stream is conducted in a separate duct, which prevents mixing with other portions of the air stream.
According to another embodiment of the present invention, a single heater unit is vertically and horizontally separated into the four heater core segments. A central coolant tank vertically separates the heater unit into symmetrical side portions. Co-planar, parallel coolant tanks are arranged at distal ends of both side portions with respect to the central coolant tank. A horizontal partition divides each of the side portions into upper and lower segments.
According to yet another embodiment, the coolant carrying tubes of the heater in a lower segment include airstream turbulence inducing elements for increasing thermal transmission in the lower segment with respect to the upper segment, thereby obtaining a comparatively higher temperature setting.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.